The present invention relates to a double-picture type television receiver for displaying two different pictures on a screen.
Recently, in accordance with increase in the number of the oblong aspect-ratio image softwares, a technique to project such an image software on a child picture of a double-picture type television receiver is devised as exemplified by the Japanese Patent Provisional Publication No. 1-303996. A conventional double-picture type television receiver will be described hereinbelow with reference to FIGS. 1 and 2. FIG. 1 shows the state that an oblong child picture F whose aspect ratio is 16:9 is formed in a picture E of a television receiver whose aspect ratio is 4:3, and FIG. 2 illustrates a circuit arrangement of the double-picture type television receiver. In FIG. 2, designated at numeral 81 is an input terminal responsive to a high-grade television signal having an aspect ratio of 16:9, and denoted at numeral 82 is a scanning line conversion circuit coupled to the input terminal 81 for converting the high-grade television signal that the number of scanning lines is 1125 per frame into a NTSC signal that the number of scanning lines is 525 per frame and then outputting it as a parent screen signal. The high-grade television signal is also supplied from the input terminal 81 to a horizontal and vertical compression circuit 83 for compressing the input signal to generate a child picture signal. The output signal of the horizontal and vertical compression circuit 83 and the output signal of the scanning line conversion circuit 2 are respectively inputted to a picture combination circuit 84 for combining both the input signals, the combination signal being supplied to a display device 85 whose aspect ratio is 4:3.
In operation, concurrently with the conversion of the number of the scanning lines, the scanning line conversion circuit 82 removes both ends of the image signal with the aspect ratio of 16:9, inputted from the input terminal 81, to the aspect ratio of the display device 85 so that the aspect ratio becomes 4:3. This results in the fact that both the ends of the parent picture of the display device 85 disappear. In the horizontal and vertical compression circuit 83, the image signal (the high-grade television signal) inputted through the input terminal 81 is compressed up to the child picture size without removing both the ends of the picture. Thus, as illustrated in FIG. 1, the entire information of the oblong image signal can be projected on the child picture F.
As described above, the conventional double-picture type television receiver is arranged assuming that the image software, i.e., the high-grade television signal, inputted is oblong. However, in spite of the fact that it is often required that the image software produced for a movie (oblong picture) is inserted into the picture of the television receiver having the aspect ratio of 4:3 so that a portion of the information of the movie is not lost but the entire information thereof can be displayed thereon, there is a problem that the conventional television receiver is not arranged to cope with such a situation.